1. Technical Field
Embodiments of the invention relate to semiconductor devices, semiconductor systems including the same, and methods of testing the same.
2. Related Art
Semiconductor devices may be designed and fabricated to include a test mode function for evaluating the operation thereof. That is, various parameters of the semiconductor devices may be measured in a test mode at a wafer level or at a package level and the tested semiconductor devices may be sorted into good chips or failed chips according to the test results.
A lot of time may be required to evaluate a lifetime of the semiconductor devices in an actual environment. Thus, it may be very important to reduce a test time for accurately estimating the lifetime of the semiconductor devices. A burn-in test has been widely used to accurately estimate the lifetime of the semiconductor devices.
The burn-in test may be performed by activating word lines of the semiconductor devices, by executing write operations and pre-charge operations of the semiconductor devices at a high temperature (e.g., at a temperature of about 125 degrees Celsius) with a high operation voltage over a normal operation voltage to repeatedly apply stresses to the semiconductor devices, and by executing read operations of the semiconductor devices to discriminate whether memory cells of each of the semiconductor devices normally operate or malfunction. The burn-in test may also be performed to sort out or screen out weak semiconductor devices having a possibility of early failure. That is, the burn-in test may be utilized to provide highly reliable semiconductor devices.